Open Source is only working under two conditions:
1) there is a big community that supports the software, i.e. contributes with code and expertise, or
2) a company that has a business model around hosting or providing value added services and add-ons.
The critical mass for developers would be 4-5 active and up to 10 contributors. If they move away, it's hard to maintain an Open Source product. That's what we should have learned from ispCP.
Unfortunately, the code is not that easy for beginners to start with writing add-ons. I tried to implement TOTP, but I stuck with the API calls. A documentation would really help. However, documentation can only be done by the developer(s).
Starting with plugins or add-ons this is how you engage people to contribute and stay. I hope Nuxwin takes some of his valuable spare time to document the API.